Theresa May’s government has told supermarkets to keep as much stock as possible in warehouses around the country in case the U.K. crashes out of the European Union without a Brexit deal, a senior official said.

The request is being made because in the worst-case scenario, a no-deal Brexit would cut the capacity of the country’s main EU trading route from the French port of Calais to Dover in southeast England to just 13 percent of the current level due to additional border checks, according to the person.

The government is also writing to businesses telling them to expect “up to six months” of port delays in the event of a no-deal Brexit, in particular at shorter crossings including the Dover-Calais route, according to another official.

As such, the government is trying to find new ways to get products into the country, the first official said. Measures include in the short term drawing up a list of priority goods, with medicines top of the list, they said. In the medium term, officials are contracting more cargo space aboard ships and looking at expanding the capacity of ports such as Sheerness.

With Parliament looking almost certain to reject Prime Minister Theresa May’s Brexit deal in a crucial vote on Tuesday, ministers and government departments are stepping up planning for a no-deal exit from the bloc. That’s because it’s the default path if the premier can’t get an agreement approved by lawmakers.

Logistical Problems

Health Secretary Matt Hancock told BBC radio Friday the likely logistical problems were “another reason” to vote for the prime minister’s deal on Dec. 11.

The senior official said a shortage of necessary temperature-controlled storage space means not all medicines can be stockpiled. Hancock told the BBC his department is buying refrigeration units to enable some drugs to be stored. He also said preparations are being made to fly medicines in and fast-track trucks with medical supplies.

“We are working on ensuring that we have aviation capacity,” he said. “If there is a serious disruption at the border, we will have prioritization—and prioritization will include medicines and medical devices.”

The senior official said the issue of how to prioritize goods throws up some conundrums for ministers, including whether to favor bags of perishable lettuce over critical parts for power stations, or auto-components needed to keep factories running and hundreds of thousands of people in work.

Supermarkets have been told of the likely problems at Dover and asked to stockpile what they can, the person said, though some products are perishable and can’t be stored for long periods.

Even in the best-case no-deal Brexit scenario, the government sees six weeks of disruption at the borders, according to another official. The government will brief organisations involved in borders on the latest No Deal planning on Friday afternoon.

The briefings were organized as part of a timetable of Brexit planning, and not due to concern that no deal is becoming an increasingly likely outcome, according to the official.